I'm truing to loosen the viscous fan nut, have the special 36mm open wrench and s-hole holding tool, but having no luck. The bolt is supposed to be right-threaded, so I think it should loosen going counter-clockwise. Is it correct? It should be torqued to only 45Nm, so I don't understand, why it would not loosen.
Any advice, somebody?

Thanks.

Correct left to loosen fan clutch on an ML.Someone overtightened it! You can thread them on and barely tighten them the direction of fan spins its not falling off.
I would load both tools as to break it loose and at the same time have someone shock the nut surface with a long drift or punch and hammer
it should come loose. If that dont work a little heat from a propane torch may be needed. good luck Tim

Thanks, Tim. I succeeded in loosening it.